using System;

using System.Collections.Generic;

using System.Net;

​

namespace SudokuAI

{

    public class Solver {

        public Board Solve(Board board) {

            //Solution goes here

            return board;

        }

        public static void Main(){

​

            //Easy

            TestPuzzle("/Easy/Puzzle185Easy.sd");

            TestPuzzle("/Easy/Puzzle186Easy.sd");

            TestPuzzle("/Easy/Puzzle187Easy.sd");

            TestPuzzle("/Easy/Puzzle188Easy.sd");

            TestPuzzle("/Easy/Puzzle189Easy.sd");

            TestPuzzle("/Easy/Puzzle190Easy.sd");

            //Medium

            TestPuzzle("/Medium/Puzzle185Medium.sd");

            TestPuzzle("/Medium/Puzzle186Medium.sd");

            TestPuzzle("/Medium/Puzzle187Medium.sd");

            TestPuzzle("/Medium/Puzzle188Medium.sd");

            TestPuzzle("/Medium/Puzzle189Medium.sd");

            //Hard

            TestPuzzle("/Hard/HardProblem187.sd");

            TestPuzzle("/Hard/HardProblem188.sd");

            TestPuzzle("/Hard/HardProblem189.sd");

            TestPuzzle("/Hard/HardProblem190.sd");

        }

        public static void TestPuzzle(string file){

            Board board = new Board(new List<List<int>>());

            var client = new WebClient();

            var str = client.DownloadString("https://raw.githubusercontent.com/Cprice1771/SudokuTester/master/SudokuUnitTest/Input"+file);

            board.Parse(str);

            Solver solver = new Solver();

            board = solver.Solve(board);

            if (board.Solved)

                Console.WriteLine("Success");

            else

                Console.WriteLine("Failed");

        }

    }

    public class Board : List<List<int>>

    {

        protected bool Equals(Board other)

        {

                for (int i = 0; i < 9; i++)

                    for (int j = 0; j < 9; j++)

                        if (this[i][j] != other[i][j])

                            return false;

​

                return true;

        }

        public bool Solved{ 

            get{

                return true;    

                }

        }

​

        public override int GetHashCode()

        {

            int sum = 0;

​

            for (int i = 0; i < 9; i++)

                for (int j = 0; j < 9; j++)

                    sum += this[i][j];

​

            return sum;

        }

​

        public Board(IEnumerable<List<int>> board): base(board)

        {

​

        }

​

        public Board(IEnumerable<List<int>> board, string file)

            : base(board)

        {

            Parse(file);

        }

​

        //Clears out the current board and replaces it with the new board from the file

        public void Parse(string file)

        {

​

            Clear();

​

            string[] lines = file.Split(new[]{"\n"},StringSplitOptions.None);

            foreach (string line in lines)

            {

                Add(new List<int>());

​

                for (int i = 0; i < line.Length; i++)

                {

                    if (line[i] == ',')

                        this[Count - 1].Add(-1);

                    else

                    {

                        this[Count - 1].Add(Int32.Parse(line.Substring(i, 1)));

                        i++;

                    }

                }

​

                //edge case for when the line ends in an empty cell

                if (this[Count - 1].Count == 8)

                    this[Count - 1].Add(-1);

​

            }

​

        }

​

        /// <summary>

        /// Returns true if the given board has a blank

        /// </summary>

        /// <returns></returns>

        public bool Unsolved

        {

            get

            {

                foreach (List<int> row in this)

                    foreach (int num in row)

                        if (num == -1)

                            return true;

​

                return false;

​

            }

        }

​

        internal List<int> GetPossibleSolutions(int row, int col)

        {

            List<int> solutions = new List<int>();

​

            for (int num = 1; num < 10; num++)

                solutions.Add(num);

            foreach (int num in GetRowNums(row))

                solutions.Remove(num);

​

            foreach (int num in GetColoumnNums(col))

                solutions.Remove(num);

​

            foreach (int num in GetQuadNums(row, col))

                solutions.Remove(num);

​

            return solutions;

​

        }

​

        private List<int> GetQuadNums(int row, int col)

        {

            int quad = GetQuad(row, col);

            List<int> nums = new List<int>();

​

            switch (quad)

            {

                case 1:

                    for (int i = 0; i < 3; i++)

                        for (int j = 0; j < 3; j++)

                            nums.Add(this[i][j]);

                    break;

                case 2:

                    for (int i = 0; i < 3; i++)

                        for (int j = 3; j < 6; j++)

                            nums.Add(this[i][j]);

                    break;

                case 3:

                    for (int i = 0; i < 3; i++)

                        for (int j = 6; j < 9; j++)

                            nums.Add(this[i][j]);

                    break;

                case 4:

                    for (int i = 3; i < 6; i++)

                        for (int j = 0; j < 3; j++)

                            nums.Add(this[i][j]);

                    break;

                case 5:

                    for (int i = 3; i < 6; i++)

                        for (int j = 3; j < 6; j++)

                            nums.Add(this[i][j]);

                    break;

                case 6:

                    for (int i = 3; i < 6; i++)

                        for (int j = 6; j < 9; j++)

                            nums.Add(this[i][j]);

                    break;

                case 7:

                    for (int i = 6; i < 9; i++)

                        for (int j = 0; j < 3; j++)

                            nums.Add(this[i][j]);

                    break;

                case 8:

                    for (int i = 6; i < 9; i++)

                        for (int j = 3; j < 6; j++)

                            nums.Add(this[i][j]);

                    break;

                case 9:

                    for (int i = 6; i < 9; i++)

                        for (int j = 6; j < 9; j++)

                            nums.Add(this[i][j]);

                    break;

                default:

                    throw new FormatException("Invalid Quad Given");

            }

​

            return nums;

​

        }

​

        private int GetQuad(int row, int col)

        {

            int quad = -1;

​

            if (row > 5)

            {

                if (col > 5)

                    quad = 9;

                else if (col > 2)

                    quad = 8;

                else if (col >= 0)

                    quad = 7;

            }

            else if (row > 2)

            {

                if (col > 5)

                    quad = 6;

                else if (col > 2)

                    quad = 5;

                else if (col >= 0)

                    quad = 4;

            }

            else

            {

                if (col > 5)

                    quad = 3;

                else if (col > 2)

                    quad = 2;

                else if (col >= 0)

                    quad = 1;

            }

​

            return quad;

        }

​

        private List<int> GetColoumnNums(int col)

        {

            List<int> foundNumbers = new List<int>();

​

            foreach (List<int> row in this)

            {

                if (row[col] != -1)

                    foundNumbers.Add(row[col]);

            }

​

            return foundNumbers;

        }

​

        private List<int> GetRowNums(int row)

        {

            List<int> foundNumbers = new List<int>();

​

            foreach (int num in this[row])

            {

                if(num != -1)

                    foundNumbers.Add(num);

            }

​

            return foundNumbers;

        }

​

        public int GetEmptySpaceCount()

        {

            int count = 0;

            foreach (List<int> row in this)

                foreach (int num in row)

                    if (num == -1)

                        count++;

            return count;

​

        }

​

        public override bool Equals(object obj)

        {

            if (!(obj is Board)) return false;

​

            Board other = obj as Board;

            for (int i = 0; i < 9; i++)

                for (int j = 0; j < 9; j++)

                    if (this[i][j] != other[i][j])

                        return false;

​

            return true;

        }

​

        public override string ToString()

        {

            string output = "";

​

            for (int i = 0; i < 9; i++)

            {

                for (int j = 0; j < 9; j++)

                    output += this[i][j] + " ";

​

                output += "\n";

            }

​

            return output;

​

        }

​

        public Board Clone()

        {

            List<List<int>> cloneList = new List<List<int>>();

​

            for (int i = 0; i < 9; i++)

            {

                cloneList.Add(new List<int>());

                for (int j = 0; j < 9; j++)

                    cloneList[i].Add(this[i][j]);

            }

​

            return new Board(cloneList);

​

        }

​

    }

}